1. Field of the Invention
The present invention relates to an optical apparatus such as a digital camera or a digital video camera, and a focusing method, and in particular to a technique for driving an image pickup lens which the optical apparatus has.
2. Description of the Related Art
Some image pickup apparatuses such as digital cameras and digital video cameras are configured to be able to use a shooting method in which a focus lens is manually driven to focus on a shooting subject so that the rack focus speed (focusing) can be freely adjusted. This shooting method will hereafter be referred to as “manual focus shooting”.
In relation to manual focus shooting, there has been proposed a technique of displaying a warning when a focus lens is moved in a wrong direction by mistake with respect to a subject (see Japanese Laid-Open Publication (Kokai) No. 2008-298956). According to this technique, a focus lens is never moved in a wrong direction by mistake, and moreover, the rack focus speed can be freely adjusted.
According to the technique described in Japanese Laid-Open Publication (Kokai) No. 2008-298956, however, a final focusing accuracy for a subject lacks stability because it depends on checking of the focus by a user or visual recognition of a distance meter provided in a lens barrel.